Autoantibody profile in a cohort of Algerian patients with systemic sclerosis

Abstract

Aim: To describe the autoantibody profile in a cohort of Algerian patients with systemic sclerosis (SSc) and to determine clinical associations between SSc-related autoantibodies, disease subtypes and specific clinical features.

Methods: Consecutive Algerian patients with SSc were included in the present study. In addition to clinical characterization, all subjects underwent autoantibody testing using indirect immunofluorescence, immunoenzymatic, and line immunoblot assays.

Results: A total of 150 patients were included in this study, 103 (68.7%) had limited cutaneous SSc (lcSSc), 42 (28%) had diffuse cutaneous SSc (dcSSc) and 5 (3.3%) had sine cutaneous scleroderma. One hundred thirty-five (90.0%) patients were positive for SSc-related autoantibodies, including 63 (42%) with more than one autoantibody. The two most frequent autoantibodies were anti-topoisomerase I (ATA) (76; 50.7%) and anti-SSA/Ro (49; 32.7%). Only 23 (15.3%) patients were positive for anticentromere; 9 (6%) were positive for anti RNA polymerase III; 5 (3.3%) for anti-U3 RNP; 3 (2%) for anti Th/To; 25 (16.7%) for anti-U1 RNP; 11 (7.3%) for anti-PM/Scl and 4 (2.7%) for anti-Ku. Anti-topoisomerase I was associated with dcSSc (p <0.0001), interstitial lung disease (ILD) (p <0.0001) and digital ulcers (p <0.0001). Anti-U3 RNP was associated with pulmonary arterial hypertension (PAH) (p=0.031).

Conclusion: Notable similarities and differences in the prevalence of SSc-related autoantibodies were found in our population when compared to other ethnic groups. ATA and anti-U3 RNP may be a reliable biomarker for ILD and PAH. Further studies should be conducted to better understand the ethnic influence on disease expression and autoantibody production.

Keywords: Algeria; autoantibodies; clinical relevance; systemic sclerosis.